In this revised application the investigators wish to pursue two main goals: expand Q2-DE to the pediatric population of patients and establish the utility of the conductance catheter method for measurement of ventricular volumes in adult patients. They also wish to study intra-operatively and at 2 and 6 weeks and 6 months postoperatively both adult and pediatric patients that had open heart surgery for a variety of valvular congenital and ischemic lesions. With the development of reliable methods to measure ventricular volume, the PI wishes to combine these data with pressure measurements to assess myocardial mechanics and edema during operation and up to six months afterwards.